The invention relates to an apparatus, to a connecting device and to an assembly for producing an electrically conductive connection between two battery modules of a battery system, in particular of an electrically driveable motor vehicle.
In electrically driveable motor vehicles, in particular electric vehicles and hybrid electric vehicles, use is made of battery systems having a multiplicity of electrically interconnected secondary battery cells, in particular for supplying electrical energy to electrical drive devices of the motor vehicles. The secondary battery cells are normally, in order to facilitate installation and uninstallation of a battery system, combined to form battery modules which are electrically interconnected.
For the electrical interconnection of battery modules, use is conventionally made of detachable connections, such as for example screw connections with cable eyelets or plug-type connections, which are arranged at terminal poles of battery cells of battery modules to be connected to one another. Both in the case of screw connections and in the case of plug-type connections, the terminal poles of the battery cells must be specially prepared for the integration of the respective connecting technique into the construction of a battery system, specifically in order to make it possible either for torques of a threaded bolt during a screw connection process to be accommodated or for a plug connector housing or a plug connector blade to be connected to the terminal poles.
It is an object of the invention for a space-saving connecting technique, which is easy to realize, for the production of an electrically conductive connection between two battery modules of a battery system to be provided or to serve as a separating device within a module.
The apparatus according to the invention for producing an electrically conductive connection between two battery modules of a battery system, in particular of an electrically driveable motor vehicle, comprises at least one clamping unit composed of metal, which at least one clamping unit can be fixedly clamped to a terminal pole of a battery cell of a battery module, or which at least one clamping unit can be fixedly clamped to a cell connector which is arranged on the terminal pole and which connects the terminal pole to a terminal pole of a further battery cell of the battery module in electrically conductive fashion.
According to the invention, an electrically conductive connection between two battery modules of a battery system can be realized using at least one clamping unit, whereby at least one conventional screw connection or plug-type connection can be omitted, such that no modification of terminal poles is necessary for the integration of these conventional connecting techniques. This is associated with a considerably simplified realization of the connecting technique according to the invention. Conventional screw connections or plug-type connections require a relatively large structural space, in particular in the case of high current carrying capacities. In comparison with this, the connecting technique according to the invention can be realized in a considerably more space-saving manner. Also, in the case of the connecting technique according to the invention, there is no need for additional assembly space to be planned in, for example for the manipulation of a conventional screw connection. Although more space-saving connecting solutions are known from the prior art, the electrical connections realized here are, owing to their relatively small size, generally greatly limited in terms of their current carrying capacity, or generate a considerable amount of heat during operation owing to their transition resistance, which heat can lead to a deterioration in cell power and to safety-critical states of battery cells and to failure of the electrically conductive connection.
The apparatus according to the invention may also comprise two or more clamping units which can each be fixedly clamped to a terminal pole of a battery cell of a battery module or to a cell connector which is arranged on the terminal pole and which connects the terminal pole to a terminal pole of a further battery cell of the battery module in electrically conductive fashion.
The clamping unit may for example be formed at least partially from copper.
With the use of the connecting technique according to the invention, it is for example possible for an arrangement of a blade on a cell contacting system for the electrically conductive connection of battery modules to be omitted. Instead, it is possible to realize direct electrical contacting with a terminal or with a cell connector. In this way, less structural space is required than in the case of corresponding conventional plug-type connections or screw connections with high current carrying capacities. Furthermore, by way of the clamping unit, a larger transmission surface can be provided than in the case of conventional plug-type connections or screw connections with high current carrying capacities, whereby it is possible, even in a relatively small structural space, for high electrical currents to be transmitted without intense generation of heat. Furthermore, by way of the clamping unit, it is possible for a larger number of contact points to be provided, which in the calculation in accordance with the constriction resistance is one of the two design criteria for a plug-type contact aside from the clamping force, than in the case of conventional plug-type connections or screw connections with high current carrying capacities, whereby it is possible, even in a relatively small structural space, for high electrical currents to be transmitted without intense generation of heat.
In one advantageous refinement, the clamping unit is of U-shaped or C-shaped form, wherein the clamping unit has two clamping limbs and a web which connects the clamping limbs to one another, and wherein, when the clamping unit is fixedly clamped to the terminal pole or to the cell connector, the clamping limbs and/or the web are/is elastically deformed, so as to generate a restoring force, as a result of contact with the terminal pole or with the cell connector. Owing to the elastic deformation of the clamping limbs and/or of the web, or the restoring force generated as a result, a clamping force is generated which is sufficient to be able to fix the clamping unit captively to a terminal pole or to a cell connector. Owing to the U-shaped or C-shaped design of the clamping unit, said clamping unit can be plugged onto a terminal pole or a cell connector such that the clamping unit engages at least partially around the terminal pole or the cell connector.
It is advantageously the case that at least one clamping limb has at least two spring lamellae which are arranged so as to run transversely with respect to the web, spaced apart from one another and parallel to one another. In this way, the clamping limb which is equipped with the spring lamellae can optimally adapt to the respective shaping of a terminal pole or of a cell connector in order to be able to provide as large as possible a contact surface for the transmission of electrical current. A clamping limb may also have more than two, for example 8, 9 or 10, spring lamellae. It is also possible for both clamping limbs to have corresponding spring lamellae.
It is preferably the case that at least one spring lamella has at least two sub-lamellae which are arranged so as to run transversely with respect to the web, spaced apart from one another and parallel to one another. This permits an even more precise adaptation of the contact surface between the clamping unit or the clamping limbs thereof and a terminal pole or a cell connector. A spring lamella may also have three or more sub-lamellae.
It is preferably the case that, on at least one spring lamella, there is formed a bead which runs in a longitudinal direction of the spring lamella. In this way, the normal force or clamping force that can be applied by a spring lamella can be varied, in particular increased, in order to improve a clamped seat of the clamping unit on a terminal pole or on a cell connector. It is also possible for a corresponding bead to be formed on two or more, in particular all, of the spring lamellae.
It is advantageously the case that, on at least two spring lamellae, there is formed in each case at least one bead, wherein the spring lamellae differ from one another in terms of the shaping of their respective beads. By way of this variation of the clamping forces, the clamping forces that can be applied by way of externally situated spring lamellae can be greater than the clamping forces that can be applied by way of internally situated spring lamellae. This permits a fine adjustment of the clamping forces that can be generated by way of the clamping unit.
In a further advantageous refinement, the apparatus comprises at least one coating, which can be arranged electrically between the terminal pole and the clamping unit, for reducing the electrical transition resistance between the terminal pole and the clamping unit, between the terminal pole and the cell connector or between the cell connector and the clamping unit. By way of the coating which reduces a transition resistance, it is possible for a transition resistance to be reduced in order to reduce heat generation at a transition between the terminal pole and the clamping unit, between the terminal pole and the cell connector or between the cell connector and the clamping unit. It is also possible for in each case one corresponding coating to be arranged both between the terminal pole and the cell connector and between the cell connector and the clamping unit.
A further advantageous refinement provides that the apparatus has at least one protective section, which at least one protective section is arranged on that side of the web of the clamping unit which faces toward the terminal pole or toward the cell connector, and which at least one protective section is formed by a section of a cell contacting system, and which at least one protective section is at least partially provided with shock protection ribs at least at an edge facing toward a clamping limb. In this way, it is possible to realize a required shock protection means in a simple manner and using a conventionally provided component of a battery system. Through the use of an existing component of a battery system to realize a shock protection means, it is not necessary to provide additional structural space for the protective section. The protective section serves to permit installation and uninstallation of the clamping unit without electric shocks.
In a further advantageous refinement, the apparatus comprises at least one contacting unit which is connectable in electrically conductive fashion to the web of the clamping unit and by means of which the clamping unit is connectable in electrically conductive fashion to a flexible electrical conductor. The contacting unit can be connected to the web of the clamping unit by way of a welded connection or by way of a crimped connection. The contacting unit may be of flat and thus space-saving form.
In a further advantageous refinement, the apparatus comprises at least one housing which accommodates the clamping unit and which is composed of electrically insulating material and which has two elastically deformable protective limbs which are arranged parallel to one another and to the clamping limbs, wherein, on at least one protective limb, on a side of the protective limb which faces toward the respective other protective limb, there is arranged at least one protective rib which runs parallel to the spring lamellae and which engages from the outside between two mutually adjacently arranged spring lamellae in such a way that, when the clamping unit is not fixedly clamped to the terminal pole or to the cell connector, the spacing between the protective rib and the protective limb situated opposite said protective rib is smaller than the spacing of the spring lamellae to the clamping limb situated opposite said spring lamellae, and in such a way that, when the clamping unit is fixedly clamped to the terminal pole or to the cell connector, the spacing between the protective rib and the protective limb situated opposite said protective rib is equal to the spacing of the spring lamellae to the clamping limb situated opposite said spring lamellae. Since it is the case that, when the clamping unit is not fixedly clamped to the terminal pole or to the cell connector, the spacing between the protective rib, which engages between two mutually adjacently arranged spring lamellae, and the protective limb situated opposite said protective rib is smaller than the spacing of the spring lamellae to the clamping limb situated opposite said spring lamellae, it is the case that, when the clamping unit is not fixedly clamped to the terminal pole or to the cell connector, the protective rib forms a shock protection means in a space-saving manner. When the clamping unit is plugged onto a terminal pole or a cell connector, the protective rib is forced outward, with elastic deformation of the respective protective limb, such that a clamping limb of the clamping unit can come into physical contact with the terminal pole or with the cell connector. It is also possible for two or more corresponding protective ribs to be arranged on a protective limb. It is also possible for both protective limbs to be equipped with corresponding protective ribs. As electrically insulating material, use may be made, in particular, of plastic or a fiber composite plastic. The protective ribs may engage between shock protection ribs of a protective section, formed by a section of a cell contacting system, of the apparatus, in order to further improve the shock protection action.
It is advantageously the case that at least two protective ribs which run parallel to the spring lamellae are arranged spaced apart from one another on the protective limb, wherein those ends of the protective ribs which are averted from the web of the clamping unit are connected to one another by way of a common connecting web. In this way, the protective ribs are connected to one another to form a unit, which is associated with easier manipulation of the protective ribs and easier handling of the apparatus.
A further advantageous embodiment provides that the apparatus has at least one housing which accommodates the clamping unit and which is composed of electrically insulating material and which has two protective limbs arranged parallel to one another and to the clamping limbs and has at least one protective section which runs on that side of the web of the clamping unit which faces toward the cell connector and parallel to the web of the clamping unit, wherein at least one protective projection which runs parallel to the protective limbs is arranged on that side of the protective section which faces toward the cell connector. The protective projection renders the clamping unit substantially inaccessible from the connecting side of the housing, in order to realize a shock protection means in a space-saving manner. The protective section may also have two or more protective projections projecting in the longitudinal direction of the protective projection in the direction of the cell connector. The protective section of the housing may interact with a section of a cell contacting system in order to improve the shock protection action. As electrically insulating material, use may be made in particular of plastic or of a fiber composite material.
The connecting device according to the invention for producing an electrically conductive connection between two battery modules of a battery system, in particular of an electrically driveable motor vehicle, comprises at least one flexible electrical conductor and at least one apparatus according to one of the abovementioned refinements or any desired combination thereof, which at least one apparatus is connected in electrically conductive fashion to the flexible electrical conductor. The advantages and embodiments mentioned above in conjunction with the apparatus are correspondingly associated with the connecting device.
Owing to the flexibility of the electrical conductor, by contrast to the conventional use of rigid connections, tolerance compensation is possible between the battery modules or battery cells thereof that are to be electrically connected to one another. The connecting device may also have two apparatuses which are connected in electrically conductive fashion to one another by way of a flexible electrical conductor.
The assembly according to the invention for producing an electrically conductive connection between two battery modules of a battery system, in particular of an electrically driveable motor vehicle, comprises at least one cell connector by way of which terminal poles of two battery cells of a battery module are connectable to one another in electrically conductive fashion, and at least one apparatus according to one of the abovementioned refinements or any desired combination thereof. The advantages and embodiments mentioned above in conjunction with the apparatus are correspondingly associated with the assembly.
The clamping unit of the apparatus may in this case be connected in electrically conductive fashion by way of the cell connector to a terminal pole of a battery cell. The assembly may also have two or more apparatuses. Furthermore, the assembly may have a connecting device as mentioned above.
In an advantageous refinement, the assembly comprises at least one housing which accommodates the clamping unit and which is composed of electrically insulating material and which has two protective limbs arranged parallel to one another and to the clamping limbs, wherein the protective limbs are connected to one another by way of at least one protective rib which runs transversely with respect to the protective limbs and which runs on that side of the web of the clamping unit which faces toward the cell connector,                wherein the clamping limbs are of identical form and each have spring lamellae, wherein, on the cell connector, there is formed at least one recess which is open in the direction of the web of the clamping unit and which is aligned with mutually oppositely situated free spaces between in each case two mutually adjacently arranged spring lamellae of the clamping limbs, wherein the protective rib runs through the free spaces and through the recess,        wherein the protective rib is designed such that it forms, on that side of the housing which faces toward the cell connector, a receptacle which is arranged within a receptacle formed on that side of the clamping unit which faces toward the cell connector.        
By way of the protective rib or the receptacle, which is delimited by the protective rib, on that side of the web of the clamping unit which faces toward the cell connector, a shock protection means conforming to IPXXB is formed in a space-saving manner. The protective limbs may also be connected to one another by way of two or more protective ribs, wherein the number must be correspondingly adapted to free spaces between adjacent spring lamellae and to receptacles on the cell connector. The protective ribs may interact with a section of a cell contacting system of a battery system in order to improve the shock protection action. As electrically insulating material, use may be made in particular of plastic or of a fiber composite material.
In a further advantageous refinement, the cell connector has at least one connecting section, which at least one connecting section is of substantially M-shaped form in longitudinal section and which at least one connecting section has two connecting blades which run parallel to the clamping limbs and by way of which the cell connector is connectable to the terminal pole, wherein at least one clamping unit can be fixedly clamped to at least one connecting blade. The connecting blades may be designed to be considerably narrower than a terminal pole of a battery cell. The cell connector may, in order to produce its respective shaping, be punched out of a metal sheet and deformed. The connecting blades may be used both in the case of parallel-connected cells and in the case of series-connected cells.
It is advantageously the case that at least one clamping unit of the apparatus can be fixedly clamped to each connecting blade, wherein the clamping units are accommodated in a common housing of the assembly, wherein each clamping unit is arranged between in each case two protective limbs, which run parallel to the clamping limbs of the clamping units and are arranged spaced apart from one another, of the housing, wherein all protective limbs of the housing are connected to one another by way of a common web of the housing. The clamping units arranged on the connecting blades can be designed to be considerably smaller than a clamping unit arranged directly on a terminal pole. The protective limbs of the housing form a shock protection means, in particular because the protective limbs which enclose a clamping unit between them are arranged relatively close together. The housing is formed from an electrically insulating material, in particular plastic or fiber composite material.
A further advantageous refinement provides that at least one clamping unit and the cell connector are designed such that the clamping unit is connectable to the cell connector by way of a clip-type connection. This provides reliable protection against automatic release of the clamping unit from the cell connector. Furthermore, the housing of the apparatus may be connected to a cell contacting system of a battery system by way of a detent mechanism.
Further details, features and advantages of the invention will emerge from the following description and from the figures, in which:
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.